The U.S. military, at the request of host nations in the region, is no longer identifying the specific land-based aircraft carrying out airstrikes in Iraq, a defense official told Military Times on Tuesday.

When airstrikes against the Islamic State began Aug. 8, a Pentagon spokesman identified the aircraft involved as carrier-based F/A-18s. But when land-based aircraft joined the mission, U.S. Central Command identified them only generically, as fighters, bombers or drones.

If CENTCOM specifies which land-based aircraft are taking part in the mission, it would be possible to deduce where they are based, and host nations have asked not to publicize the fact that airstrikes against Iraq are being launched from their countries, the defense official said.

Such concerns are not unique to current operations in Iraq, the official said. CENTCOM cannot publicly acknowledge that it has certain forces in the region because doing so would upset domestic politics in those countries.

The Pentagon has been more open about which aircraft are attacking the Islamic State. For instance, during an Aug. 11 news conference, Army Lt. Gen. William C. Mayville Jr., director of operations at the Joint Staff, told reporters that F-15Es, F-16s and MQ-1 Predators were taking part in the airstrikes.

As of Monday, 68 airstrikes had been launched against targets in Iraq, of which 35 were in support Kurdish and Iraqi forces fighting to retake the Mosul Dam, CENTCOM announced in a news release.

When asked by a reporter on Monday if he was concerned about “mission creep” in Iraq, President Obama said the U.S. airstrikes are not a sustainable solution to the Islamic State threat.

“I have been firm from the start that we are not reintroducing thousands of U.S. troops back on the ground to engage in combat,” Obama said. “We’re not the Iraqi military. We’re not even the Iraqi air force. I am the commander-in-chief of the United States armed forces, and Iraq is going to have to ultimately provide for its own security.”